Lake Housatonic Authority

What is Lake Housatonic?

The Lake is a long and narrow impoundment of the Housatonic River [River] located in Southwestern Connecticut in Fairfield and New Haven counties. It is located at 73DEG 8MIN 36SEC longitude and 41DEG 19MIN 36 SEC latitude. The towns of Derby, Monroe, Oxford, Seymour, and Shelton border the Lake. Public access is available at Indian Well State Park in Shelton.

The Lake is one of three major impoundments of the River. The Lake is formed by two hydroelectric generating dams, the Derby Dam located at the southern end of the Lake and the Zoar Dam located at the Northern end of the Lake. These dams control the water flow and cause the Lake to behave more like a river. Several streams feed the Lake from both the East and West sides. These streams include Round Hill Brook, White Hills Brook, Indian Hole Brook, Curtiss Brook, Pink House Cove Brook, Great Hills Brook, Spruce Brook, Four Mile Brook, Eight Mile Brook, as well as many unnamed streams. The Lake spans an area of approximately 328.2 acres, has a volume of approximately 134,386,085 cubic feet and has a watershed of approximately 1,007,360 acres (1,574 square miles). This translates to a maximum storage capacity of approximately 10 billion gallons. The water retention time is approximately 15 hours (King’s Mark, 1988).

The bedrock under the Lake is made up of bands of crystalline, metamorphic rocks called schist and gneisses with a narrow band of Butress Dolerite igneous rock at the southern end. Sand and gravel covers the majority of the lakebed with glacial till deposits covering the remainder. The substrate is made up of ledge, boulder, gravel, coarse sands and sand/silt fines. The shoreline is made up of a mix of steep and flat terrain. The terrain is supported by an underlying layer of bedrock. Common elodea, water milfoil, and wild celery are abundant in the Lake (King’s Mark, 1988).

The Lake supports a mix of both seasonal and year round residences in all towns but Monroe as well as several commercial building in all towns except Oxford and light industrial at its southern most point in Derby only. Many of the residences on the shore line have septic systems on site and well water systems. A state road, Route 34, also known as Roosevelt Drive, borders the east side and drains into the Lake. Indian Wells, a state park/beach, is located in Shelton on the Lake’s western shore. The Lake supports many forms of recreation including boating, water sports, swimming, and fishing.

The last recorded mean depth of the Lake is 2.8 meters (9.2 feet) and the maximum depth is 7.9 meters (25.9 feet).  The summer transparency [T] is typically 2 meters, color [C] is typically 10, summer chl-a is 22 ppb, total Nitrogen [N] is 700, and total phosphorous [P] is 51. As such, the Lake is classified as Class B and Eutrophic. Bacteria counts are typically low (Norvell & Frink, 1984).